Mww type zeolite substance, precursor substance therefor, and process for producing these substances

ABSTRACT

A process for easily synthesizing a zeolite substance containing an element having a large ionic radius in the framework at a high ratio. This process comprises the following first to fourth steps: First Step: a step of heating a mixture containing a template compound, a compound containing a Group 13 element of the periodic table, a silicon-containing compound and water to obtain a precursor (A); Second Step: a step of acid-treating the precursor (A) obtained in the first step; Third Step: a step of heating the acid-treated precursor (A) obtained in the second step together with a mixture containing a template compound and water to obtain a precursor (B); and Fourth Step: a step of calcining the precursor (B) obtained in the third step to obtain a zeolite substance.

This Application claims the priority of an application based on U.S.Application Ser. No. 60/363313 (filed on Mar. 12, 2002).

TECHNICAL FIELD

The present invention relates to zeolite substance having a structurecode MWW, a precursor therefor having a layered structure, and processesfor producing these substances.

More specifically, the present invention relates to a zeolite substancehaving a structure code MWW to be produced by utilizing a post-synthesismethod, a precursor for the zeolite substance having a layeredstructure, and a process for producing these substances.

BACKGROUND ART

Generally, “zeolite” has been long a generic term of crystalline porousaluminosilicates and these are (SiO₄)⁴⁻ and (AlO₄)⁵⁻ having atetrahedral structures as the basic units of the structure. However, inrecent years, it has been clarified that a structure peculiar oranalogous to zeolite is present in many other oxides such asaluminophosphate.

International Zeolite Association (hereinafter simply referred to as“IZA”) organizes the frameworks of zeolite and zeolite-like materials inAtlas of Zeolite Structure Types, 5th edition, edited by Ch. Baerlocher,W. M. Meier and D. H. Olson, Elsevier, 2001 (Non-Patent Document 1)(hereinafter simply referred to as “Atlas”) and each framework isdenoted by an IZA code composed of three alphabetical letters.

With respect to the details of the history thereof, “Zeolite no Kagakuto Kogaku (Science and Engineering of Zeolite” by Yoshio Ono and TateakiYajima (compilers), Kodansha K. K., published on Jul. 10, 2000(Non-Patent Document 2) may be referred to.

The definition of “zeolite” as used in the present invention is based onthe definition described in Zeolite no Kagaku to Kogaku (Science andEngineering of Zeolite) that zeolite includes not only aluminosilicatebut also those having an analogous structure, such as metallosilicate.

In the present invention, a structure code composed of threealphabetical capital letters derived from the names of standardsubstances initially used for the clarification of structure, approvedby IZA, is used for the structure of zeolite. This includes thoserecorded in Atlas and those approved in the 5th and later editions.

Further, unless otherwise indicated specifically, the “aluminosilicate”and “metallosilicatell as used in the present invention are not limitedat all on the difference such as crystalline/non-crystalline orporous/non-porous and include “aluminosilicates” and “metallosilicates”in all properties.

The “molecular sieve” as used in the present invention is a substancehaving an activity, operation or function of sieving molecules by thesize and includes zeolite. This is described in detail in “MolecularSieve” of Hyojun Kagaku Yogo Jiten (Glossary for Standard Chemistry),compiled by Nippon Kagaku Kai, published by Maruzen on Mar. 30, 1991(Non-Patent Document 3).

Zeolite and zeolite-like materials have various frameworks and theframework approved by IZA includes 133 species until the issue of Atlas,5th edition. Even at present, new frameworks are being discovered andthe frameworks approved by IZA are introduced on the homepage thereof.

However, the frameworks reported all are not always useful in industryand industrially useful frameworks are relatively limited. It isconsidered that the industrial value is generally determined by theuniqueness of structure, the production cost and the like. Amongframeworks discovered in recent years, MWW structure is particularlyuseful in industry and attracting an attention. The MWW structure is aframework peculiar to zeolite represented by MCM-22.

According to Zeolite no Kagaku to Koqyo (Science and Engineering ofZeolite), a patent application for a synthesis method of MCM-22 wasfiled by Mobil in 1990 (JP-A (unexamined published Japanese patentapplication) 63-297210 (Patent Document 1)) and thereafter, Leonowicz etal. reported that MCM-22 is a hexagonal zeolite having a particular porestructure. A representative substance thereof is borosilicate having thefollowing unit cell composition:H_(2.4)Na_(3.1)[Al_(0.4)B_(5.1)Si_(66.5)O₁₄₄]

The characteristic feature in the framework is to have two pore networksindependent of each other in the direction perpendicular to the c axis(in the plane direction of layer). One of these pore networks is presentbetween layers and a cocoon-like supercage (0.71×0.71×1.82 nm) istwo-dimensionally connected to six supercages therearound. Thesupercages are directly connected to each other by a 10-membered ringand therefore, a relatively large molecule can enter into the pore ascompared with a tunnel-like 10-membered ring pore. Another of the abovepore networks is present within a layer and a two-dimensional network isformed by 10-membered ring zigzagged pores. ITQ-1 which is pure silica,SSZ-25 and the like have the same framework.

As for the production process for MWW-type zeolite, there is a processutilizing a hydrothermal synthesis at around 150° C. using a relativelyinexpensive hexamethyleneimine as the crystallizing agent.Aluminosilicate can be synthesized at an Si/Al molar ratio of 15 to 35.Substances obtained by the hydrothermal synthesis and showing aproduction behavior different from zeolite are generally a layeredprecursor (commonly called MCM-22(P)) and are characterized in that whencalcined, dehydration condensation takes place between layers and MCM-22having a zeolitic 3-dimensional structure is formed.

However, in recent studies, it has been reported that MCM-49 produced bythe same preparation method while charging a large amount of an alkalimetal has the same framework as MCM-22. This reveals that not a layeredprecursor but aluminosilicate having an MWW structure can be directlyobtained as a product of the hydrothermal synthesis (see, S. L. Lawtonet al., J. Phys. Chem., 100, 3788 (1996) (Non-Patent Document 4)).

The MWW structure has a characteristic feature not seen in conventionalzeolites as described above, and aluminosilicate having the MWWstructure is known to exhibit high activity and selectivity in thesynthesis of ethylbenzene or cumene as compared with zeolite havingother structures or catalysts other than zeolite and it is consideredthat such zeolites have already been used in many plants over the world.

Also, there is an attempt to obtain a catalyst having higher performanceby utilizing the layered precursor obtained in the synthesis of MWWstructure. More specifically, MCM-36 obtained by crosslinking thelayered precursor with silica (see, for example, W. J. Roth et al.,Stud. Surf. Sci. Catal., 94, 301 (1995) (Non-Patent Document 5)),thin-layered substance ITQ-2 obtained by exfoliation of layers (see, forexample, A. Corma et al., Microporous Mesoporous Mater., 38, 301 (2000)(Non-Patent Document 6)) and the like have been reported and it isstated that these exhibit higher activity than aluminosilicate having amere MWW structure.

However, even in the above-mentioned high-performance catalysts, thereactivity thereof is basically derived from the layered structureconstituting the MWW structure and when compared with zeolites havingother frameworks, these are classified into substances analogous tozeolite having an MWW structure. The synthesis of such a zeolite-likelayered compound is characterized by having a step of treating thelayered precursor MCM-22(P) in an aqueous solution containing asurfactant such as hexadecyltrimethylammonium bromide, and therebyswelling or exfoliating a layer.

On the other hand, since the MWW structure has a characteristic featurenot seen in other zeolite structures as described above, acharacteristic catalytic activity or adsorbing activity attributable tothe MWW framework structure can be expected. This characteristicactivity is not necessarily limited to the above-describedaluminosilicate but metallosilicate containing an element other thanaluminum in the framework (or skeleton) is also expected to provide thesame effect. From this expectation, various studies have been made onthe synthesis of metallosilicate having an MWW structure. However, thetransition element represented by titanium, vanadium and chromium, andthe typical element of the 5th period or more represented by indium andtin, which are expected to show remarkably different properties fromaluminosilicate in general (not limited to MWW structure), have a verylarge ionic radius as compared with silicon or aluminum and therefore,such an element is usually difficult to introduce into the framework. Bythe simple direct synthesis method of allowing a compound containingsuch an element to be present together in the raw material forsynthesizing zeolite, a desired metallosilicate cannot be obtained inmany cases.

For introducing the element into the framework, various methods havebeen proposed. Representative examples of the method employed for theMWW structure include a post-synthesis method (a method of oncesynthesizing zeolite and after-treating it to introduce a heteroelementinto the framework; this is generally called a post-synthesis incontract with the direct synthesis) and an improved direct method.

With respect to the post-synthesis method, for example, U.S. Pat. No.6,114,551 (Patent Document 2) discloses a process for synthesizingmetallosilicate by a post-synthesis method, where aluminosilicate havingan MWW structure is once synthesized, the whole or a part of aluminum isremoved out from the aluminosilicate by a dealuminating treatment suchas contact with SiCl₄ in gas phase to form defects, and a compoundcontaining an element to be introduced, such as TiCl₄, is contacted withthe dealuminated product.

As for the improved direct method, Wu et al. have reported an examplewhere ferrisilicate is obtained by designing the step of adding an ironcompound to a gel (P. Wu et al., Chem. Commun., 663 (1997) (Non-PatentDocument 7)).

Further, for Ti which is difficult to introduce into the frame, asynthesis method using boron as a structure supporting agent has beenrecently developed (P. Wu et al., Chemistry Letters, 774 (2000)(Non-Patent Document 8)).

Also, a method for obtaining MWW-type titanosilicate has been proposed,where a large amount of boron is added to a starting raw material, anMWW precursor MCM-22(P) having both boron and titanium in the frameworkis synthesized by utilizing the function of boron as a structuresupporting agent and after removing boron, if desired, by an acidtreatment, the obtained precursor is calcined. The titanosilicate havingan MWW structure prepared by this method is reported to exert acharacteristic catalytic activity (P. Wu et al., J. Phys. Chem. B, 105,2897 (2001) (Non-Patent Document 9)).

However, according to these methods, particularly the post-synthesismethod wherein a zeolite is caused to contact a compound of an elementto be introduced thereinto, most part of the elements intended tointroduce cannot be introduced into the framework and remain as aresidue in the pore. In order to improve the introduction efficiency,one important point is to select a compound which can easily enter intopores of zeolite. However, there is a problem that in general a compoundcontaining an element intended to introduce and having a sufficientlysmall molecular size is not available on the market.

Further, on use as a catalyst or the like, in the case where the rawmaterial is a dealuminated product of MWW-type aluminosilicate as inU.S. Pat. No. 6,114,551, a side reaction ascribable to aluminumremaining in the framework sometimes brings about a serious problem suchas causing side reactions to provide by-products. The same problemoccurs in the direct method using boron as a structure supporting agent,that is, boron cannot be satisfactorily removed even by an acidtreatment and a large amount of boron remains in the framework or pores,or if strict conditions are adapted for the process of removing boron byan acid treatment or the like so as to enhance the removal ratio ofboron, components which must remain in the frame are alsodisadvantageously removed at the same time. Moreover, the propersynthesis conditions greatly change depending on the element intended tointroduce and the compound containing the element and therefore, thesemethods are not very good in terms of the general-purpose applicability.

(Patent Document 1)

-   -   JP-A 63-297210

(Patent Document 2)

-   -   U.S. Pat. No. 6,114,551

(Non-Patent Document 1)

-   -   Atlas of Zeolite Structure Types, 5th edition, edited by Ch.        Baerlocher, W. M. Meier and D. H. Olson, Elsevier, 2001

(Non-Patent Document 2)

-   -   “Zeolite no Kagaku to Kogaku (Science and Engineering of        Zeolite” by Yoshio Ono and Tateaki Yajima (compilers),        Kodansha K. K., published on Jul. 10, 2000

(Non-Patent Document 3)

-   -   “Molecular Sieve” of Hyojun Kagaku Yogo Jiten (Glossary for        Standard Chemistry), compiled by Nippon Kagaku Kai, published by        Maruzen on Mar. 30, 1991.

(Non-Patent Document 4)

-   -   S. L. Lawton et al., J. Phys. Chem., 100, 3788 (1996)

(Non-Patent Document 5)

-   -   W. J. Roth et al., Stud. Surf. Sci. Catal., 94, 301 (1995)

(Non-Patent Document 6)

-   -   A. Corma et al., Microporous Mesoporous Mater., 38, 301 (2000)

(Non-Patent Document 7)

-   -   P. Wu et al., Chem. Commun., 663 (1997)

(Non-Patent Document 8)

-   -   P. Wu et al., Chemistry Letters, 774 (2000)

(Non-Patent Document 9)

-   -   P. Wu et al., J. Phys. Chem. B, 105, 2897 (2001)

DISCLOSURE OF INVENTION

An object of the present invention is to provide a process for easilysynthesizing zeolite having an MWW structure, particularly, zeolitecontaining an element having a large ionic radius, which is difficult tointroduce by conventional synthesis methods, in the framework at a highratio.

As a result of earnest study, the present inventors have found thatzeolite having a structure of IZA structure code MWW and containing anelement having a large ionic radius in the frame at a high ratio can besimply and easily synthesized by a specific production process. Thepresent invention has been accomplished based on this finding.

That is, the present invention (I) is a process for producing a zeolitesubstance having an MWW structure, comprising the following first tofourth steps:

First Step:

-   -   a step of heating a mixture containing a template compound, a        compound containing a Group 13 element of the periodic table, a        silicon-containing compound and water to obtain a precursor (A);        Second Step:    -   a step of acid-treating the precursor (A) obtained in the first        step;        Third Step:    -   a step of heating the acid-treated precursor (A) obtained in the        second step together with a mixture containing a template        compound and water to obtain a precursor (B); and        Fourth Step:    -   a step of calcining the precursor (B) obtained in the third step        to obtain a zeolite substance.

The present invention (II) is a zeolite substance which contains atleast one element selected from the elements belonging to Groups 3 to14, in the Period 4 or more of the periodic table; and can besynthesized by the production process of a zeolite substance having anMWW-type structure of the present invention (I).

The present invention comprises, for example, the following matters.

[1] A process for producing a zeolite substance having an MWW structure,comprising the following first to fourth steps:

First Step:

-   -   a step of heating a mixture containing a template compound, a        compound containing a Group 13 element of the periodic table, a        silicon-containing compound and water to obtain a precursor (A);        Second Step:    -   a step of acid-treating the precursor (A) obtained in the first        step;        Third Step:    -   a step of heating the acid-treated precursor (A) obtained in the        second step together with a mixture containing a template        compound and water to obtain a precursor (B); and        Fourth Step:    -   a step of calcining the precursor (B) obtained in the third step        to obtain a zeolite substance.

[2] The process for producing a zeolite substance according to [1],wherein the compound containing a Group 13 element of the periodic tableused in the first step is a boron-containing compound.

[3] The process for producing a zeolite substance according to [1] or[2], wherein the following first-2 step is performed between the firststep and the second step, and the substance obtained in the first-2 stepis used instead of the precursor (A) in the second step:

First-2 Step:

-   -   a step of calcining a part or entirety of the precursor (A)        obtained in the first step.

[4] The process for producing a zeolite substance according to any oneof [1] to [3], wherein the following third-2 step is performed betweenthe third step and the fourth step, and the substance obtained in thethird-2 step is used instead of as the precursor (B) in the fourth step:

Third-2 Step:

-   -   a step of acid-treating a part or entirety of the precursor (B)        obtained in the third step.

[5] The process for producing a zeolite substance according to any oneof [1] to [4], wherein in the third step, a compound containing at leastone element selected from the elements belonging to Groups 3 to 14 ofthe periodic table is present together with the acid-treated precursor(A) obtained in the second step.

[6] The process for producing a zeolite substance according to any oneof [1] to [5], wherein the template compound is a nitrogen-containingcompound.

[7] The process for producing a zeolite substance according to [6],wherein the nitrogen-containing compound is an amine and/or quaternaryammonium compound.

[8] The process for producing a zeolite substance according to [6],wherein the nitrogen-containing compound is at least one member selectedfrom the group consisting of piperidine, hexamethyleneimine and amixture of piperidine and hexamethyleneimine.

[9] The process for producing a zeolite substance according to any oneof [2] to [8], wherein the boron-containing compound is at least onemember selected from the group consisting of boric acid, borate, boronoxide, boron halide and trialkylborons.

[10] The process for producing a zeolite substance according to any oneof [1] to [9], wherein the silicon-containing compound is at least onemember selected from the group consisting of silicic acid, silicate,silicon oxide, silicon halide, fumed silicas, tetraalkyl ortho-silicateand colloidal silica.

[11] The process for producing a zeolite substance according to any oneof [2] to [10], wherein the ratio between boron and silicon in themixture of the first step is boron:silicon=0.01 to 10:1 in terms of themolar ratio.

[12] The process for producing a zeolite substance according to any oneof [2] to [11], wherein the ratio between boron and silicon in themixture of the first step is boron:silicon=0.05 to 5:1 in terms of themolar ratio.

[13] The process for producing a zeolite substance according to any oneof [1] to [12], wherein the ratio between water and silicon in themixture of the first step is water:silicon=5 to 200:1 in terms of themolar ratio.

[14] The process for producing a zeolite substance according to any oneof [1] to [13], wherein the ratio between the template compound andsilicon in the mixture of the first step is templatecompound:silicon=0.1 to 5:1 in terms of the molar ratio.

[15] The process for producing a zeolite substance according to any oneof [1] to [14], wherein the heating temperature in the first step isfrom 110 to 200° C.

[16] The process for producing a zeolite substance according to any oneof [1] to [15], wherein the acid used for the acid-treated in the secondstep is a nitric acid.

[17] The process for producing a zeolite substance according to any oneof [1] to [16], wherein the heating temperature in the third step isfrom 110 to 200° C.

[18] The process for producing a zeolite substance according to any oneof [1] to [17], wherein the calcining temperature in the fourth step isfrom 200 to 700° C.

[19] The process for producing a zeolite substance according to any oneof [3] to [18], wherein the calcining temperature in the first-2 step isfrom 200 to 700° C.

[20] The process for producing a zeolite substance according to any oneof [1] to [19], wherein in the third step, the acid-treated precursor(A) obtained in the second step and the mixture containing a templatecompound and water are previously mixed and then heated.

[21] The process for producing a zeolite substance according to any oneof [1] to [20], wherein a dry gel method of charging the acid-treadedprecursor (A) obtained in the second step and the mixture containing atemplate compound and water while isolating the precursor (A) and themixture from each other, and contacting the vapor of the mixturecontaining a template compound and water with a mixture of a compoundcontaining at least one element selected from Group 3 to Group 14elements of the periodic table, and the precursor (A), in the thirdstep.

[22] A precursor obtained in the third step of the process according toany one of [1]-[21].

[23] The precursor according to 22 which has a layered structure.

[24] The process for producing a zeolite substance according to any oneof [5] to [21], wherein the at least one element selected from theelements belonging to Groups 3 to 14 of the periodic table is at leastone element selected from the group consisting of titanium, zirconium,vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese,iron, cobalt, nickel, zinc, gallium, indium, tin and lead.

[25] A metallosilicate substance having an MWW structure containing atleast one element selected from the elements belonging to Groups 3 to14, in the Period 4 or more of the periodic table.

[26] A metallosilicate substance having an MWW structure containing atleast one element selected from the elements belonging to Groups 3 to14, in the Period 5 or more of the periodic table.

[27] A metallosilicate substance having an MWW structure containing atleast one element selected from the group consisting of titanium,zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten,manganese, iron, cobalt, nickel, zinc, gallium, indium, tin and lead.

[28] A metallosilicate substance for a zeolite substance having an MWWstructure produced by the process according to any one of [1]-[21] and[24].

[29] A layered precursor metallosilicate substance for a zeolitesubstance having an MWW structure containing at least one elementselected from the elements belonging to Groups 3 to 14, in the Period 4or more of the periodic table.

[30] A layered precursor metallosilicate substance for a zeolitesubstance having an MWW structure containing at least one elementselected from the elements belonging to Groups 3 to 14, in the Period 5or more of the periodic table.

[31] A layered precursor metallosilicate substance for a zeolitesubstance having an MWW structure containing at least one elementselected from the group consisting of titanium, zirconium, vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron,cobalt, nickel, zinc, gallium, indium, tin and lead.

[32] A layered precursor metallosilicate substance for a zeolitesubstance having an MWW structure produced by the process according toany one of [1]-[21] and [24].

[33] A zeolite substance produced by the process according to any one of[1]-[21] and [24].

[34] A process for producing a layered precursor for a zeolitesubstance, comprising the following first to third steps:

First Step:

-   -   a step of heating a mixture containing a template compound, a        compound containing a Group 13 element of the periodic table, a        silicon-containing compound and water to obtain a precursor (A);        Second Step:    -   a step of acid-treating the precursor (A) obtained in the first        step;        Third Step:    -   a step of heating the acid-treated precursor (A) obtained in the        second step together with a mixture containing a template        compound and water to obtain a layered precursor.

[35] A layered precursor for a zeolite substance, produced by theprocess according to [34].

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is schematic view for explaining the typical synthesis method foran MWW type zeolite substance according to the present invention.

FIG. 2 is a graph showing a powder X-ray diffraction pattern of a tinsilicate provided in Example 1.

FIG. 3 is a graph showing a UV spectrum of the tin silicate provided inExample 1.

FIG. 4 is a graph showing a powder X-ray diffraction pattern of the tinsilicate precursor substance provided in Example 1.

FIG. 5 is a graph showing a UV spectrum of the zirconium silicateprovided in Example 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinbelow, the present invention will be described in detail withreference to the accompanying drawings as desired. In the followingdescription, “%” and “part(s)” representing a quantitative proportion orratio are those based on mass (or weight), unless otherwise notedspecifically.

(Process for Producing Zeolite Substance)

First, the present invention (I) is described. The present invention (I)is a process for producing a zeolite substance having an MWW-typestructure, comprising the following first to fourth steps:

First Step:

-   -   a step of heating a mixture containing a template compound, a        compound containing a Group 13 element of the periodic table, a        silicon-containing compound and water to obtain a precursor (A);        Second Step:    -   a step of acid-treating the precursor (A) obtained in the first        step;        Third Step:    -   a step of heating the acid-treated precursor (A) obtained in the        second step together with a mixture containing a template        compound and water to obtain a precursor (B); and        Fourth Step:    -   a step of calcining the precursor (B) obtained in the third step        to obtain a zeolite substance.

The above steps are schematically shown in the schematic view of FIG. 1.

The zeolite substance having an MWW-type structure can be synthesized,for example, by a conventionally known direct synthesis method or apost-synthesis method such as atom planting. In synthesizing the zeolitesubstance by atom planting, this may be attained, for example, bysynthesizing a molecular sieve with an MWW structure containing boronand/or aluminum and after removing at least a part of boron or aluminumby a water vapor treatment or the like, followed by contacting themolecular sieve with an element-containing compound such as metalchloride. The details of the atom planting process are available in page142 of the above-mentioned “Zeolite no Kagaku to Kogaku”.

In view of the production efficiency, the zeolite substance having anMWW structure of the present invention may preferably be produced by theproduction process of the present invention (I). That is, the processfor producing a zeolite substance having an MWW structure of the presentinvention (I) is characterized by comprising four steps, that is, a stepof heating a mixture containing a template compound, a compoundcontaining a Group 13 element of the periodic table, asilicon-containing compound and water to obtain a precursor (A), a stepof acid-treating the obtained precursor (A), a step of heating theacid-treated precursor (A) together with a mixture containing a templatecompound, an element-containing compound and water to obtain a precursor(B), and a step of calcining the obtained precursor (B) to obtain azeolite substance having an MWW structure.

(First Step)

The first step of the above production process is described. The firststep in the process for producing a zeolite substance having an MWWstructure of the present invention (I) is a step for heating a mixturecontaining a template compound, a compound containing a Group 13 elementof the periodic table, a silicon-containing compound and water, tothereby obtain a precursor (A).

The term “template compound” as used herein means a compound having anactivity of specifying the structure, particularly the pore shape, atthe time of synthesizing zeolite having an MWW structure. The templatecompound is not particularly limited as long as it can be removedafterward by calcination. Specific examples of the template compound maygenerally include nitrogen-containing compounds, preferably an amineand/or quaternary ammonium compound. Examples of the amine may generallyinclude a nitrogen-containing compound and specific examples includepiperidine, hexamethyleneimine and/or a mixture of piperidine andhexamethyleneimine. However, the present invention is not limitedthereto.

The compound containing a Group 13 element of the periodic table (i.e.,the 18-group type periodic table based on the IUPAC Recommendation in1990 as described in “Kagaku Binran¹¹ (Handbook for Chemistry), 4threvised edition, page I-56), which can be used in the first step, is notparticularly limited but may preferably be a boron compound, an aluminumcompound or a gallium compound, more preferably a boron compound, inview of the easy provision of an intended MWW structure precursor, andeasy removal in the subsequent step. Specific preferred examples thereofinclude a boric acid, however, this compound can also be used in theform of a borate such as sodium borate.

The silicon-containing compound which can be used in the first step isnot particularly limited. Specific examples thereof include silicicacid, silicate, silicon oxide, silicon halide, fumed silicas, tetraalkylortho-silicate and colloidal silica. In any case, a high-purity compound(e.g., those having a silicon proportion of 98% or more with respect toall the metal elements to be contained therein) is preferred.Particularly, in the case of colloidal silica, a smaller alkali content(e.g., those having an alkali content of 0.01 or less in terms ofalkali/silicon molar ratio) is more preferred.

The ratio between boron and silicon in a mixture of the first step maypreferably be, in terms of the molar ratio, in the range ofboron:silicon=0.01-10:1, more preferably in the range ofboron:silicon=0.05-5:1, more preferably in the range ofboron:silicon=0.3-3:1. As describe hereinafter, the precursor (A) isintended to be synthesized, under an alkali metal-free condition, it isnecessary to use a large amount of boron, the ratio may preferably be inthe range of boron:silicon=0.3-2:1, more preferably in the range ofboron:silicon=1-2:1.

The ratio between water and silicon in the mixture of the first step maypreferably be, in terms of the molar ratio, water:silicon=5 to 200:1,more preferably water:silicon=15 to 50:1. If this ratio is too small, itis difficult to obtain a mixture having a good quality. If this ratio istoo large, the productivity will become worse.

The ratio between the template compound and silicon in the mixture ofthe first step may preferably be, in terms of the molar ratio, templatecompound:silicon=0.1 to 5:1, more preferably templatecompound:silicon=0.3 to 3:1, still more preferably template compoundsilicon=0.5 to 2:1. If this ratio is too small, it is difficult toobtain an intended product. If this ratio is too large, a considerableamount of the template compound can be wasted, and such a process is noteconomical.

Further, it is also useful to add a seed crystal in addition to theseraw materials. In this case, it is sometimes possible to expect aneffect of shortening the crystallization time or providing a producthaving a small particle size. As the seed crystal, it is preferred touse a substance having an MWW structure or a structure similar to MWWsuch as precursor therefor having a layered structure (e.g., MCM-22(P)), which has preliminarily been synthesized. It is particularlypreferred to use a layered-structure precursor for an MWW type zeolitesubstance containing boron. For example, it is possible to add a part ofa precursor (A) obtained in the past first step, to a mixture to be usedin the first step as the seed crystal. The timing for the additionthereof is not particularly limited, but it is possible that all theother raw materials are mixed, the seed crystal is added to theresultant mixture, and thereafter the mixture is stirred and thenheated. As the amount of the seed crystal to be added, the molar ratioof silicon contained in the seed crystal to the silicon in thesilicon-containing compound to be used as main raw material maypreferably be a ratio of seed crystal:main raw material=0.0001-0.2:1,more preferably 0.001-0.05:1. If the addition amount is to small, it isdifficult to obtain the above-mentioned effect. If the addition amountis to large, the productivity will become lower.

As another additive, it is possible to add a compound including analkali metal such as sodium or potassium, and in such a case thecrystallization time can sometimes be shortened. In general, thepresence of alkali metal can provide a tendency such that it can inhibitthe introduction of an element other than boron, aluminum, and siliconinto the framework of a zeolite substance, or it can promote thecondensation of a compound including the element to be incorporated intothe framework to form the condensation product of such a compound perse. As an example, it is a well-known fact that titanium does not enterthe zeolite framework in a good manner, if an alkali metal is present inthe system in the case of synthesis of titanosilicate such as TS-1, andthe added titanium source is incorporated into the product as titania orthe species similar to titania. However, in the present invention, evenwhen an alkali metal is used in the first step, it is also possible tosubstantially remove the alkali metal in the acid treatment (secondstep), prior to the step for introducing the metal species into theframework (third step). Accordingly, it is also possible to use analkali metal in the first step of this invention, and it is possiblethat an alkali metal is present in a molar ratio of alkalimetal:silicon:=0.0001-0.2:1, more preferably about 0.001-0.1:1. As thealkali metal source, there are hydroxides, nitric acid salts, chlorides,sulfuric acid salts, salt of other metal acid, but a hydroxide or boratemay most preferably be used.

The heating temperature in the first step is not particularly limitedbut in the case of synthesizing a precursor (A), this may preferably beperformed under hydrothermal reaction conditions. The term “hydrothermalreaction” as used herein means, as described in “Hydrothermal Reaction”of Hyojun Kagaku Yogo Jiten (Glossary for Standard Chemistry), compiledby Nippon Kagaku Kai, Maruzen (Mar. 30, 1991), a synthesis ormodification reaction of a substance performed in the presence ofhigh-temperature water, particularly high-temperature high-pressurewater. In particular, a synthesis reaction using the hydrothermalreaction is referred to as “hydrothermal synthesis”. Accordingly, theheating in the first step may preferably be performed by placing amixture containing a template compound, a boron-containing compound, asilicon-containing compound and water in a closed container such asautoclave, under hydrothermal synthesis conditions of applying apressure while heating. The temperature may preferably be from 110 to200° C., more preferably from 120 to 190° C.

If the temperature in the hydrothermal synthesis is less than thisrange, the objective product may not be obtained or even if obtained,the heating may take a long time and this is not practical. On the otherhand, if the temperature exceeds this range, the purity of the obtainedzeolite substance disadvantageously decreases.

The hydrothermal synthesis time is usually from 2 hours to 30 days,preferably from 3 hours to 10 days. If the hydrothermal synthesis timeis less than this range, crystallization may proceed insufficiently tofail in obtaining a high-performance precursor (A). On the other hand,even if the hydrothermal synthesis is performed for a time periodexceeding this range, the performance of the precursor (A) is notsubstantially enhanced but rather adverse effects may be caused such asconversion into other phase or increase of the particle size and this itnot preferred.

(Second Step)

The second step is described below. The second step is a step ofacid-treating the precursor (A) obtained in the first step or first-2step to obtain a deboronated silicate.

The precursor (A) obtained in the first step may be acid-treated as itis but when the precursor is calcined (first-2 step) before the acidtreatment and thereafter acid-treated, boron inside the framework can bemore efficiently removed. Thus, utilizing this first-2 step ispreferable. Hereinbelow, the precursors obtained in the first step andthe first-2 step are inclusively referred to as “precursor (A)”.

The term “acid treatment” as used herein means contacting with an acid,more specifically, to contact the precursor (A) obtained in the firststep with a solution containing an acid or with an acid itself. Thecontacting method is not particularly limited and a method of sprayingor coating an acid or an acid solution on the precursor (A) or a methodof dipping the precursor (A) in an acid or an acid solution may be used.The method of dipping the precursor (A) in an acid or an acid solutionis preferred because this dipping method is simple and easy.

The acid used for this step may be an inorganic acid, an organic acid ora salt thereof. Specific preferred examples of the inorganic acidinclude a hydrochloric acid, a sulfuric acid, a nitric acid and aphosphoric acid. Specific preferred examples of the organic acid includea formic acid, an acetic acid, a propionic acid and a tartaric acid.Examples of the salt thereof include an ammonium salt.

In the case of using the acid as a solution, the solvent therefor is notparticularly limited. Specific examples of the solvent include water,alcohols, ethers, esters and ketones. Among these, water is preferred.

The acid concentration is also not particularly limited. The preferredrange thereof can vary depending on the temperature. When the acidconcentration is low, the removal of boron is less liable to occur. Whenacid concentration is too high and the temperature is too high, theprecursor (A) per se can be dissolved. Accordingly, the acid is suitablyused in a concentration of 0.1 to 10 mol/liter. The treatment may beperformed at a temperature of 0 to 200° C. but may preferably beperformed at 50 to 180° C., more preferably from 60 to 150° C. Thetreatment time is from 0.1 hour to 3 days, preferably from 2 hours to 1day.

It is also possible to conduct the cycle of (the first-2 step secondstep) plural times, in order to minimize the residual content of boron.

(Third Step)

The third step is described below. The third step is a step of heatingthe deboronated silicate obtained in the second step, together with amixture containing a template compound, an element-containing compoundand water to obtain a precursor (B).

The “template compound” as used herein is, similarly to that used in thefirst step, a compound having an activity of specifying the structure,particularly the pore shape at the synthesis of a zeolite having an MWWstructure. This compound is not particularly limited as long as it canbe removed afterward by calcination. Examples thereof generally includea nitrogen-containing compound and specific examples thereof includepiperidine, hexamethyleneimine and/or a mixture of piperidine andhexamethyleneimine, however, the present invention is not limitedthereto.

The template compound used in the third step may be the same as ordifferent from the template compound used in the first step. In view ofthe efficiency of metal introduction, the template compound used in thethird step may preferably be hexamethyleneimine.

The element-containing compound which can be used in the third step isnot particularly limited, as long as it contains a group 3-14 element(particularly, as a metal at least one member selected from the groupconsisting of titanium, zirconium, vanadium, niobium, tantalum,chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, zinc,gallium, indium, tin and lead). Specific examples of, for example, thetitanium-containing compound include titanium oxide, titanium halide andtetraalkyl ortho-titanates, however, the present invention is notlimited thereto. Among these, titanium halide and tetraalkylortho-titanates are preferred in view of easy and simple handleability.Specifically, titanium tetrafluoride, tetraethyl ortho-titanate,tetrapropyl ortho-titanate, tetrabutyl ortho-titanate and the like aresuitably used.

Examples of the zirconium-containing compound include zirconium oxide,zirconium halide and zirconium tetraalkoxides, however, the presentinvention is not limited thereto. Among these, zirconium halide andzirconium tetraalkoxides are preferred in view of simple and easyhandleability. Specifically, zirconium tetrafluoride, zirconiumtetraethoxide, zirconium tetrabutoxide and the like are suitably used.

Examples of the vanadium-containing compound include vanadium oxide,vanadium halide and vanadium trialkoxide oxides, however, the presentinvention is not limited thereto. Among these, vanadium halide andvanadium trialkoxide oxides are preferred in view of easy and simplehandleability. Specifically, vanadium trichloride and vanadiumoxytriisopropoxide are suitably used.

Examples of the niobium-containing compound include niobium oxide,niobium halide and niobium tetraalkanoates, however the presentinvention is not limited thereto. Among these, niobium tetraalkanoatesare preferred in view of easy and simple handleability. Specifically,niobium tetrakis(2-ethylhexanoate) is suitably used.

Examples of the tantalum-containing compound include tantalum oxide,tantalum halide and tantalum disulfide, however, the present inventionis not limited thereto. Specifically, tantalum disulfide is suitablyused.

Examples of the chromium-containing compound include chromium acetate,chromium nitrate and chromium halide, however, the present invention isnot limited thereto. Specifically, chromium nitrate is suitably used.

Examples of the molybdenum-containing compound include molybdenum oxide,molybdenum halide and molybdenum sulfide, however, the present inventionis not limited thereto. Specifically, molybdenum trichloride is suitablyused.

Examples of the tungsten-containing compound include tungsten oxide andtungsten halide, however, the present invention is not limited thereto.Specifically, tungsten tetrachloride is suitably used.

Examples of the manganese-containing compound include manganese oxide,manganese halide, manganese acetate and manganese acetylacetonate,however, the present invention is not limited thereto. Specifically,manganese trisacetylacetonate is suitably used.

Examples of the iron-containing compound include iron oxide, ironhalide, iron acetate and iron nitrate, however, the present invention isnot limited thereto. Specifically, iron nitrate is suitably used.

Examples of the cobalt-containing compound include cobalt oxide, cobalthalide and cobalt trisacetylacetonate, however, the present invention isnot limited thereto. Specifically, cobalt trisacetylacetonate issuitably used.

Examples of the nickel-containing compound include nickel oxide, nickelhalide, nickel nitrate and nickel acetate, however, the presentinvention is not limited thereto. Specifically, nickel nitrate, nickelacetate and the like are suitably used.

Examples of the zinc-containing compound include zinc oxide, zinchalide, zinc acetate and zinc nitrate, however, the present invention isnot limited thereto. Specifically, zinc acetate, zinc nitrate and thelike are suitably used.

Examples of the gallium-containing compound include gallium oxide,gallium halide and gallium nitrate, however, the present invention isnot limited thereto. Specifically, gallium nitrate, gallium trichloride,gallium trifluoride and like are suitably used.

Examples of the indium-containing compound include indium oxide, indiumhalide and trialkoxy indiums, however, the present invention is notlimited thereto. Specifically, indium trichloride, indium trifluoride,indium triisoproxide and the like are suitably used.

Examples of the tin-containing compound include tin oxide, tin halideand tetraalkoxy tins, however, the present invention is not limitedthereto. Specifically, tin tetrachloride, tin tetrafluoride,tetra-tert-butoxy tin and the like are suitably used.

Examples of the lead-containing compound include lead oxide, leadhalide, tetraalkoxy lead, however, the present invention is not limitedthereto. Specifically, lead acetate, lead chloride, lead nitrate, leadacetylacetonate, lead sulfate and the like are suitably used.

The precursor (B) obtained in the third step can be synthesized bypreviously mixing all of the acid-treated precursor obtained in thesecond step, a template compound, an element-containing compound andwater and heating the mixture to perform a so-called hydrothermalsynthesis similarly to the first step.

The order of mixing is not particularly limited. For example, in orderto homogenize the raw material composition, it is preferred that atfirst, a mixture liquid comprising water, a template compound, andelement-containing compound is prepared, and the acid treated precursorprovided in the second step is added to the resultant mixture. Further,the mixture liquid comprising water, a template compound, and theelement-containing compound may preferably be a uniform solution ratherthan slurry, and it is desirable to devise the kind and concentration ofthe element-containing compound or mixing condition (temperature, time)so as to obtain such a solution.

In the mixture of the third step, the ratio of the element to silicon inthe acid-treated precursor may preferably be, in terms of the molarratio, element:silicon=0.001 to 0.3:1, more preferablyelement:silicon=0.005 to 0.2:1, still more preferablyelement:silicon=0.01 to 0.2:1. The above ratio may preferably be aslarge as possible in view of the appearance of the characteristicderived from the introduced element. However, if the ratio is too large,the element can undesirably form an impurity phase by itself.

In the third step, the ratio of water to silicon in the acid-treatedprecursor may preferably be, in terms of the molar ratio,water:silicon=5 to 200:1, more preferably water:silicon=15 to 50:1. Ifthe ratio is too small, it is difficult to obtain a mixture having agood quality. If the ratio is too large, the productivity will belowered.

In the third step, the ratio of the template compound to silicon in theacid-treated precursor may preferably be, in terms of the molar ratio,template compound:silicon=0.1 to 5:1, more preferably templatecompound:silicon=0.3 to 3:1, still more preferably templatecompound:silicon=0.5 to 2:1. If this ratio is too small, it is difficultto obtain an intended product. If this ratio is too large, aconsiderable amount of the template compound can be wasted, and such aprocess is not economical.

As for the conditions of hydrothermal synthesis in the third step, thesame conditions as described for the first step may be applied. However,when a compound containing an element of 3-14 group is co-present in thethird step, it is possible that the adequate synthesis condition isconsiderably different from that in the first step. Particularly, withrespect to the temperature and time, it is desirable to select thecondition depending on the element to be co-present, so as to provide anintended precursor (B) having a high purity. As described in Examplesappearing hereinafter, when the temperature is too high, or time is toolong, the product can be changed into a substance having anotherstructure such as ZSM-39 (structure cord MTN) instead of the intendedprecursor (B).

In addition, as an embodiment of the third step, it is also possible touse a so-called dry gel method wherein a mixture (mixture X) of theacid-treated precursor provided in the second step and theelement-containing compound, and a mixture of water and the templatecompound (mixture Y) are charged separately, and the mixture (mixture X)of the acid-treated precursor provided in the second step and themetal-containing compound is caused to contact the vapor of water andthe template compound. In this case, there is a merit that the templatecompound which has not been used for the crystallization can berecovered easily.

With respect to the details of this dry gel method, e.g., page 28 of theabove-mentioned “Zeolite no Kagaku to Kogaku” may be referred to.

The mixture X can be obtained by a method wherein a solution of anelement-containing compound is dispersed in the acid-treated precursorobtained in the second step as uniformly as possible by use ofimpregnation, dipping, etc., then dried, and pulverized as desired. Thedrying can be conducted by various methods such as air drying at roomtemperature, vacuum drying at high temperature. In general, an aqueoussolution is frequently used, and therefore it is sufficient to effectthe drying at 50-80° C. for 1-24 hours. The end point of the drying issuch that the product in a crushable state.

The mixture Y may be obtained by mixing a template compound and water.

In the dry gel method, the kind of the template compound to be used, thekind of the element-containing compound to be co-present, the ratio ofthe element being co-present to silicon in the precursor, and the ratioof the template compound to silicon in the precursor may be the same asthose as described in the case of the above-described normalhydrothermal synthesis.

The ratio of water to silicon in the precursor is different from thenormal hydrothermal synthesis in the adequate range, and may preferablybe in terms of molar ratio, water:silicon=0.01-15:1, more preferably iswater:silicon=0.1-10:1.

The method of charging the mixture X and the mixture Y may be anymethod, as long as the mixture X and the mixture Y cannot be mixed witheach other unless the mixture Y is heated to be vaporized. For example,it is possible to achieve such charging by a method wherein the mixtureY is placed in the bottom of an autoclave and a container containing themixture X is hung in the middle part of the autoclave.

By the above-mentioned first to third steps, it is possible to obtainthe precursor (B) for a MWW type zeolite substance. When a compoundcontaining at least one element selected from the elements of 3 group to14 group is co-present in the third step, a precursor (B) containingsuch a metal can be obtained. When the precursor (B) is subjected to thecalcining step to be referred to as the fourth step, the precursor canbe converted into an MWW type zeolite substance when the precursor (B)is subjected to layer-exfoliation in the presence of a surfactant, in asimilar manner as in the case of ITQ-2, a thin-layered substance may beobtained. Of course, it is also possible that, in a similar manner as inthe case of MCM-36, the precursor is swollen and then treated withalkoxysilane, etc., so that pillars are formed between the layers(pillaring) to thereby obtain cross-linking type layered substance.Various kinds of metal-containing layered compounds can be produced bysuch processes.

By the above-mentioned first to third steps, it is possible to obtainthe precursor (B) for a MWW type zeolite substance (B). The formation ofthe precursor (B) can be confirmed, e.g., by the powder X-raydiffraction pattern thereof.

(Fourth Step)

The fourth step is described below. The fourth step is a step ofcalcining the precursor obtained in the third step or third-2 step toobtain a zeolite substance.

Hereinbelow, the precursors obtained in the third step and third-2 stepare inclusively referred to as “precursor (B)”.

The method for the calcination of precursor performed between the firststep and the second step (first-2 step) and in the fourth step is notparticularly limited and the calcination can be performed underconditions known for normal catalyst calcination. The calcination may beperformed in a closed system or a flow system and as long as an oxygennecessary for the burning of the template compound is present. Thecalcination in the air is most easy, but it is also possible that forthe purpose of avoiding the excessive heat production, the precursor isheated to a predetermined temperature in an inert gas stream such asnitrogen to degrade the template inside, and then oxygen is introducedto thereby remove the residue by burning. The calcination temperaturemay preferably be from 200 to 700° C., more preferably from 300 to 650°C., most preferably from 400 to 600° C. If the calcination temperatureis less than 200° C., the template compound may not be satisfactorilyremoved, whereas if it exceeds 700° C., the MWW-type crystal structuremay be broken and this disadvantageously causes an adverse effect on theprecursor performance in the case of calcination of the first-2 step andon the quality of the resultant zeolites in the case of calcination ofthe fourth step.

The temperature rising rate at the calcinations may preferably be 1°C./min but is not limited thereto if breakage of the MWW-type structuredoes not occur.

The production process of an MWW-type zeolite substance of the presentinvention (I) is described more specifically below, while referring toFIG. 1 as a view for schematically showing the series of these steps.Referring to FIG. 1, the production process of the present invention (I)is a method wherein a layered precursor (A) to be converted into anMWW-type borosilicate is synthesized from a boric acid and asilicon-containing compound using piperidine or hexamethyleneimine asthe template (the above procedure is the first step), and acid-treatingthe layered precursor borosilicate (the above procedure is the secondstep) to synthesize a deboronated silicate (acid-treated precursor (A)).Prior to the second step, it is also possible to calcine the layeredprecursor to be converted into the MWW-type borosilicate (the first-2step). Then, an element-containing layered precursor (B) is synthesizedfrom the deboronated silicate and an element-containing compound usingpiperidine or hexamethyleneimine as the template (the above procedure isthe third step), and calcining the element-containing layered precursor(the above procedure is the fourth step) to remove the template, wherebya zeolite substance having an MWW structure is obtained.

The zeolite substance which can be obtained by the production process ofthe present invention (I) can be used as it is as a catalyst in anoxidation reaction, however, the oxide of element, which is generated asa result of condensation of element itself present in the zeolitesubstance obtained by the production process and not contributing to theoxidation reaction, can be at least partially removed by contacting thezeolite substance with an acid. By this contacting with an acid, anMWW-type zeolite catalyst having higher performance can be obtained.

The “contacting with an acid” as used herein is effective even if it isperformed before or after or both before and after the calcination inthe fourth step, but this treatment is most effective when applied inthe precursor (B) state before the calcination (third-2 step). Thereby,the production of an oxide of element that may be generated by thecalcination of a by-product due to condensation of the element compounditself can be greatly inhibited.

The “contacting with an acid” used here has the same meaning as the“contacting with an acid” described in the second step and as for thecontacting method, the acid used for the contacting, the concentrationof acid used for the contacting, the timing of contacting and when theacid is used as a solution, the solvent and the like, the conditionsdescribed in the second step can be applied.

The present invention (II) is described below. The present invention(II) is, e.g., a layered precursor and a zeolite substance which can besynthesized by the production process of a zeolite substance having anMWW-type structure and a layered precursor therefor of the presentinvention (I). These layered precursor or zeolite substance contains, inaddition to silicon, at least one element selected from the groupconsisting of 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 group elements (in thefourth period or more) and gallium, indium, tin and lead. Further, thereis provided a substance wherein at least a part of these elements isincorporated into the framework of the zeolite or layered compound.

More specifically, main embodiments of the present invention (II) mayinclude the following embodiments.

-   -   (1) A metallosilicate substance having an MWW structure        containing at least one element selected from the elements        belonging to Groups 3 to 14, in the Period 4 or more of the        periodic table.    -   (2) A metallosilicate substance having an MWW structure        containing at least one element selected from the elements        belonging to Groups 3 to 14, in the Period 5 or more of the        periodic table.    -   (3) A metallosilicate substance having an MWW structure        containing at least one element selected from the group        consisting of titanium, zirconium, vanadium, niobium, tantalum,        chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel,        zinc, gallium, indium, tin and lead.    -   (4) A metallosilicate substance for a zeolite substance having        an MWW structure produced by the above-mentioned process.    -   (5) A layered precursor metallosilicate substance for a zeolite        substance having an MWW structure containing at least one        element selected from the elements belonging to Groups 3 to 14,        in the Period 4 or more of the periodic table.    -   (6) A layered precursor metallosilicate substance for a zeolite        substance having an MWW structure containing at least one        element selected from the elements belonging to Groups 3 to 14,        in the Period 5 or more of the periodic table.    -   (7) A layered precursor metallosilicate substance for a zeolite        substance having an MWW structure containing at least one        element selected from the group consisting of titanium,        zirconium, vanadium, niobium, tantalum, chromium, molybdenum,        tungsten, manganese, iron, cobalt, nickel, zinc, gallium,        indium, tin and lead.    -   (8) A layered precursor metallosilicate substance for a zeolite        substance having an MWW structure produced by the        above-mentioned process.

Further, there is a metallosilicate substance having an MWW structurecontaining, as an element other than silicon, at least one elementselected from the group consisting of titanium, zirconium, vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron,cobalt, nickel, zinc, gallium, indium, tin and lead.

Further preferably, there is a metallosilicate substance having an MWWstructure containing, in addition to silicon, at least one elementselected from the group consisting of titanium, zirconium, vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron,cobalt, nickel, zinc, gallium, indium, tin and lead, and also at leastpartially of the element are held in framework of MWW structure.

The structure code MWW is one of known molecular sieve structures andits characteristic feature is to have a pore composed of an oxygen10-membered ring, and a supercage (0.7×0.7×1.8 nm). Details on thestructure are described, for example, in Atlas, 5th ed. or can be readon the internet, the homepage of IZA Structure Commission(http://www.iza-structure.org/) (as of February, 2002). Known examplesof the molecular sieve having this structure include MCM-22 (Science,Vol. 264, 1910 (1994)), SSZ-25 (European Patent 231860), ITQ-1 (Chem.Mater., Vol. 8, 2415 (1996) and J. Phys. Chem. B, Vol. 102, 44 (1998)),ERB-1 (European Patent 203032) and PSH-3 (U.S. Pat. No. 449409). Themolecular sieve having the structure code MWW can be identified by itscharacteristic pattern on the X-ray diffraction (hereinafter simplyreferred to as “XRD¹I). As for the XRD pattern, for example, asimulation pattern of ITQ-1 can be available on the above-describedhomepage.

The characteristic diffraction pattern in the MWW structure is shown inthe Table 1. The present invention (II) is characterized in that thestructure has the following diffraction pattern. TABLE 1 Powder X-raydiffraction lines provided by MWN structure relative intensity d/Å (s:strong, m: medium, w: weak) 12.3 ± 0.6 s 11.0 ± 0.6 s  8.8 ± 0.5 s  6.2± 0.4 m  5.5 ± 0.3 w  3.9 ± 0.2 m  3.7 ± 0.2 w  3.4 ± 0.2 s

The above “d/Å” means that the unit of lattice spacing d is Angstrom.

In addition, when a transition metal is introduced into a silicate, acharacteristic absorption may appear in the visible to ultraviolet lightregion whether the characteristic absorption appears in the UV-VISspectrum can be an index of a fact that a transition metal is introducedinto a silicate framework. While the position of the absorption band maychange in various manners depending on the element to be introduced, butin some cases, the present invention (II) may be characterized in thatthere is an absorption in the region of 300 nm or shorter, particularly250 nm or shorter.

The layered precursor for an MWW type zeolite substance can also becharacterized by the XRD pattern thereof. The characteristic diffractionpattern of the layered precursor for an MWW type zeolite substance isshown in the Table 2. In one aspect, the layered precursor of thepresent invention (II) is characterized in that the precursor has thefollowing diffraction pattern. TABLE 2 Powder X-ray diffraction linesprovided by layered precursor for MWN type zeolite substance d/Årelative intensity 27.6 ± 2 m 13.5 ± 0.5 s 12.4 ± 0.6 s 11.2 ± 0.6 s 9.1 ± 0.5 m  6.8 ± 0.4 w  6.0 ± 0.4 w  4.5 ± 0.3 m  3.5 ± 0.2 w  3.4 ±0.2 s

EXAMPLES

The present invention is described in greater detail below by referringto Examples, however, these Examples only show the outline of thepresent invention and the present invention is not limited to theseExamples.

ANALYZERS IN EXAMPLES AND COMPARATIVE EXAMPLES

Elemental Analysis Method of Zeolite Substance

A sample was weighed into a Teflon (registered trademark of E.I. du Pontde Nemours and Company) beaker and hydrofluoric acid (50 mass %) wasadded and dissolved. Pure water was added thereto and the elementalanalysis was performed using a desk-type inductively coupled plasmaspectrometer (JY38S) manufactured by Rigaku.

Powder X-ray diffraction method (XRD)

The powder X-ray diffraction pattern of a sample was measured by usingthe following apparatus and conditions.

-   -   Apparatus: MX-Labo powder x-rays analysis apparatus mfd.        JASCOUV/VIS spectrometer V-550 mfd. by Nihon Bunko Company    -   Measurement range: 200-500 nm    -   Standard material for base line: BaSO₄

Example 1 Preparation of MWW-Type Tin Silicate

[Preparation of Borosilicate and Acid Treatment]

In 684 g of ion-exchanged water, 243.2 g of piperidine (mfd. by WakoPure Chemical Industries, Ltd., purity: 98%) (hereinafter, referred toas SPITZ) was dissolved at 25° C. to prepare an aqueous piperidinesolution. To this aqueous piperidine solution, 165.8 g of boric acid(mfd. by Wako Pure Chemical Industries, Ltd., purity: 99.5%) was addedunder vigorous stirring. The boric acid was completely dissolved understirring for 30 minutes, and thereafter 120 g of fumed silica (Ca-o-silM7D) was added thereto and the stirring was further continued for 2hours to obtain a mixture of 1.SiO₂: 0.067.B₂O₃:1.4.PI:19.H₂O in termsof molar ratio.

This mixture was transferred to a 2 liter-Teflon-made autoclave (i.e.,an autoclave having a Teflon-made liner) and stirred for 120 hours at arotation speed of 100 rpm at a temperature of 170° C. After stopping therotation, the contents were cooled to 25° C. and the solid product wasseparated from the contents by filtration and washed with ion-exchangedwater. The washing was repeated until the pH of the washing water became9 or less. The thus obtained solid product was dried at a temperature of80° C. and calcined at a temperature of 600° C. With respect to 1 g ofthe thus obtained solid product, 30ml of nitric acid of 6 mol/l wasadded so as to effect acid treatment at a temperature of 100° C. for 20hours. After the completion of the acid treatment, the solid obtained byfiltration was calcined at a temperature of 600° C. for ten hours. Themolar ratio of boron/silicon of this solid (deboronated silicate A) was0.0217. Further, with respect to 1 g of the thus obtained solid product,30 ml of nitric acid of 6 mol/l was added so as to effect acid treatmentat a temperature of 100° C. for 20 hours. After the completion of theacid treatment, the solid obtained by filtration was calcined at atemperature of 600° C. for ten hours. The molar ratio of boron/siliconof this solid (deboronated silicate B) was 0.0017.

[Preparation of Sn-MWW]

At 25° C., 14.5 g of PI (purity 98%, mfd. by Wako Pure ChemicalIndustries Co., Ltd.) was dissolved in 30 g of ion-exchanged water tothereby prepare a PI aqueous solution. To this aqueous PI solution, 1.99g of tin tetrachloride pentahydrate (mfd. by Wako Pure ChemicalIndustries, Ltd., purity: 98%) was added under vigorous stirring. Afterstirring for 30 minutes to completely dissolve the tin tetrachloride, 10g of the deborosilicate B having a boron/silicon molar ratio of 0.0017,which had been prepared in the above “preparation of borosilicate andacid treatment”, was added and the stirring was further continued for 2hours to obtain a mixture of 1SiO₂:0.033.SnO₂:1.PI:10.H₂O in terms ofmolar ratio.

This mixture was transferred to a 150 ml-volume Teflon-made autoclaveand stirred for 158 hours at a rotation speed of 40 rpm at a temperatureof 175° C. After stopping the rotation, the contents were cooled to 25°C. and the solid product was separated from the contents by filtrationand washed with ion-exchanged water. The washing was repeated until thepH of the washing water became 9 or less. The thus obtained solidproduct was dried at a temperature of 80° C., and a part of the solidproduct was used as a sample for XRD measurement. The remainder of thesolid product was calcined for 10 hours at a temperature of 600° C. Asthe final intended product, an MWW-type tin silicate was obtained. ThisMWW-type tin silicate had a tin/silicon molar ratio of 0.025 and aboron/silicon molar ratio of 0.0016, and 76 mol % of tin charged wasincorporated into the product.

The XRD pattern and UV spectrum of the thus obtained tin silicate areshown in FIG. 2 and 3, respectively. In the XRD pattern, the diffractionlines shown in Table 1 which was characteristic to the MWW typestructure was recognized. In the UV spectrum, absorption was recognizedin the region of 250 nm or less, it was found that at least a part ofthe tin was incorporated into the framework.

The XRD pattern of layered precursor for the tin silicate is shown inFIG. 4. The diffraction pattern group shown in Table 2 which ischaracteristic to the layered precursor for the MWW type zeolitesubstance shown was recognized.

Example 2 Preparation of MWW-Type Zirconium Silicate

In 15 g of ion-exchanged water and 5 g of an aqueous hydrogen peroxidesolution (mfd. by Wako Pure Chemical Industries, Ltd., purity: 31%), 7.2g of PI (mfd. by Wako Pure Chemical Industries, Ltd., purity: 98%) wasdissolved at 25° C. to prepare an aqueous PI solution. To this aqueousPI solution, 1.25 g of zirconium (IV) butoxide in 1-butanol solution(mfd. by Wako Pure Chemical Industries, Ltd., purity: 85%) was addedunder vigorous stirring. After stirring for 30 minutes to completelydissolve the zirconium(IV) butoxide, 5 g of deborosilicate having aboron/silicon molar ratio of 0.0017, which had been prepared in Example1, was added and the stirring was further continued for 2 hours toobtain a mixture of 1.SiO₂:0.033.ZrO₂:1.PI:15.H₂O in terms of molarratio.

This mixture was transferred to a 150 ml-volume Teflon-made autoclaveand stirred for 158 hours at a rotation speed of 40 rpm at a temperatureof 175° C. After stopping the rotation, the contents were cooled to 25°C. and the solid product was separated from the contents by filtrationand washed with ion-exchanged water. The washing was repeated until thepH of the washing water became 9 or less. The thus obtained solidproduct was dried at a temperature of 80° C. and calcined for 10 hoursat a temperature of 600° C. As the final intended product, an MWW-typezirconium silicate was obtained. This MWW-type zirconium silicate had azirconium/silicon molar ratio of 0.015 and a boron/silicon molar ratioof 0.0016, and 45 mol % of zirconium charged was incorporated into theproduct.

In the XRD pattern of the above zirconium silicate, the diffractionlines shown in Table 1 was recognized. In the UV spectrum shown in FIG.5, absorption was recognized in the region of 250 nm or less.

Example 3 Preparation of MWW Type Vanadium Silicate

At 25° C., 7.2 g of PI (purity 98%, mfd. by Wako Pure ChemicalIndustries Co., Ltd.) was dissolved in 15 g of ion-exchanged water tothereby prepare a PI aqueous solution. 0.68 g of vanadium compound,vanadium oxytriisopropoxide (purity 95%, mfd. by Aldrich Co.) was addedto this piperidine aqueous solution under vigorous stirring. Thevanadium compound was completely dissolved under stirring for 30minutes, and then 5 g of the deboronated silicate B having a 0.0017molar ratio of the boron/silicon which had been prepared in Example 1,and the stirring was continued for further two hours, to thereby obtaina mixture having a molar ratio of 1.SiO₂:0.017.V₂O₅:1.PI:10H₂O.

This mixture was transferred to a 150 ml-volume Teflon-made autoclaveand stirred for 15 hours at a rotation speed of 40 rpm at a temperatureof 175° C. After stopping the rotation, the contents were cooled to 25°C. and the solid product was separated from the contents by filtrationand washed with ion-exchanged water. The washing was repeated until thepH of the washing water became 9 or less. The thus obtained solidproduct was dried at a temperature of 80° C. and calcined for 10 hoursat a temperature of 6000C. As the final intended product, an MWW-typevanadium silicate was obtained.

In the XRD pattern of the above vanadium silicate, the diffraction linesshown in Table 1 was recognized. In the UV spectrum, absorption wasrecognized in the region of 250 nm or less.

Comparative Example 1 Preparation of MWW Type Vanadium Silicate

A mixture was prepared in the same manner as in Example 3, and thismixture was transferred to a 150 ml-volume Teflon-made autoclave andstirred for 132 hours at a rotation speed of 40 rpm at a temperature of175° C. After stopping the rotation, the contents were cooled to 25° C.and the solid product was separated from the contents by filtration andwashed with ion-exchanged water. The washing was repeated until the pHof the washing water became 9 or less. The thus obtained solid productwas dried at a temperature of 80° C.

In the XRD pattern of the above product, the diffraction lines shown inTable 1 was not recognized, and instead, the diffraction lines shown inTable 3 which can be assigned to the MTN structure was recognized. It isconsidered that the layered precursor for an MWW type structure wasconverted into the MTN type structure by conducting the hydrothermalreaction for a long time. TABLE 3 XRD lines of Comparative Example d/Årelative intensity 11.2676 w 3.8781 w 5.8624 s 5.6044 s 4.8440 m 4.4579m 3.9587 m 3.7355 s 3.4373 m 3.2782 s 3.0640 w

Example 4 Preparation of MWW Type Titanosilicate (Normal HydrothermalSynthesis Method)

At 25° C., 14.5 g of PI (purity 98%, mfd. by Wako Pure ChemicalIndustries Co., Ltd.) was dissolved in 30 g of ion-exchanged water tothereby prepare a PI aqueous solution. 2.0 g of tetrabutyl orthotitanate(purity 95%, mfd. by Wako Pure Chemical Industries Co., Ltd.) was addedto this PI aqueous solution under vigorous stirring. The tetrabutylorthotitanate was completely hydrolyzed under stirring for 30 minutes,and then 10 g of the deboronated silicate B having a molar ratio of0.0017 of the boron/silicon which had been prepared in Example 1, andthe stirring was continued for further two hours, tto thereby obtain amixture having a molar ratio of 1.SiO₂:0.033.TiO₂:1.PI:10.H₂O.

This mixture was transferred to a 150 ml-volume Teflon-made autoclaveand stirred for 15 hours at a rotation speed of 40 rpm at a temperatureof 175° C. After stopping the rotation, the contents were cooled to 25°C. and the solid product was separated from the contents by filtrationand washed with ion-exchanged water. The washing was repeated until thepH of the washing water became 9 or less. The thus obtained solidproduct was dried at a temperature of 80° C. With respect to 1 g of thethus obtained solid product, 20 ml of nitric acid of 2 mol/l was addedso as to effect acid treatment at a temperature of 100° C. for 20 hours.After the completion of the acid treatment, the solid obtained byfiltration was calcined at a temperature of 600° C. for ten hours, tothereby obtain an intended final product of MWW-Type titanosilicaste.The molar ratio of titanium/silicon of this solid was 0.0233. The molarratio of boron/silicon of this solid was 0.0018.

In the XRD pattern of the thus obtained titanosilicate, the diffractionlines shown in Table 1 was recognized. In the UV spectrum thereof,absorption was recognized in the region of 250 nm or less.

Example 5 Preparation of MWW Type Titanosilicate (Dry Gel Method)

At 25° C., 0.2 g of tetrabutyl orthotitanate (purity 95%, mfd. by WakoPure Chemical Industries Co., Ltd.) was added to an aqueous solution of2 g of ion-exchanged water and 1 g of hydrogen peroxide (purity 31%,mfd. by Wako Pure Chemical Industries Co., Ltd.). The resultant mixturewas stirred for 30 minutes so as to completely promote the hydrolysis oftetrabutyl orthotitanate and the production of titanium peroxide by thereaction with hydrogen peroxide, and then the stirring was continued forfurther 30 minutes to thereby obtain a homogeneous solution. To theresultant product, 9 g of ion-exchanged water and 10 g of deboronatedsilicate A having a molar ratio of the boron/silicon of 0.0217 which hadbeen prepared in Example 1 were added, the stirring was continued for 10minutes. Thereafter, under stirring, water content was vaporized at atemperature of 100° C. for three hours, to thereby obtain a solidmixture having a molar ratio of 1.SiO₂:0.033.TiO₂.

This mixture was transferred to a 5 ml-Teflon-made beaker, and chargedto a Teflon-made autoclave, to which 1.5 g of ion-exchanged water and2.5 g of PI (purity 98%, mfd. by Wako Pure Chemical Industries Co.,Ltd.) had preliminarily been charged, so that the aqueous PI solutionwas placed separately, and the reaction system was subjected to staticheating for 158 hours at a temperature of 170° C. After 158 h-heating,the contents were cooled to 25° C. and the solid product was separatedfrom the contents by filtration and washed with ion-exchanged water. Thewashing was repeated until the pH of the washing water became 9 or less.The thus obtained solid product was dried at a temperature of 80° C.With respect to 1 g of the thus obtained solid product, 100 ml of nitricacid of 2 mol/l was added so as to effect acid treatment at atemperature of 100° C. for 20 hours. After the completion of the acidtreatment, the solid obtained by filtration was calcined at atemperature of 600° C. for ten hours, to thereby obtain a final intendedproduct of MWW-type titanosilicate. The molar ratio of titanium/siliconof this MWW-type titanosilicate was 0.0167, and the molar ratio ofboron/silicon thereof was 0.0018.

In the XRD pattern of the thus obtained titanosilicate, the diffractionlines shown in Table 1 was recognized. In the UV spectrum thereof,absorption was recognized in the region of 250 nm or less.

Industrial Applicability

As described hereinabove, according to the present invention, it isclear that, according to the production process of the present invention(i.e., process for producing a zeolite substance having an MWW-typestructure), elements having a large ionic radius, which are difficult tobe incorporated into the framework, can be introduced with goodefficiency, as compared with conventionally known methods for producinga zeolite substance having an MWW-type structure, and a zeolitesubstance having such an element in the framework and having an MWW-typestructure, and a layered precursor therefor, which have been heretoforedifficult to obtain, can be obtained.

1. A process for producing a zeolite substance having an MWW structure,comprising the following first to fourth steps: First step: a step ofheating a mixture containing a template compound, a compound containinga Group 13 element of the periodic table, a silicon-containing compoundand water to obtain a precursor (A); Second Step: a step ofacid-treating the precursor (A) obtained in the first step; Third Step:a step of heating the acid-treated precursor (A) obtained in the secondstep together with a mixture containing a template compound and water toobtain a precursor (B); and Fourth Step: a step of calcining theprecursor (B) obtained in the third step to obtain a zeolite substance.2. The process for producing a zeolite substance according to claim 1,wherein the compound containing a Group 13 element of the periodic tableused in the first step is a boron-containing compound.
 3. The processfor producing a zeolite substance according to claim 1 or 2, wherein thefollowing first-2 step is performed between the first step and thesecond step, and the substance obtained in the first-2 step is usedinstead of the precursor (A) in the second step: First-2 Step: a step ofcalcining a part or entirety of the precursor (A) obtained in the firststep.
 4. The process for producing a zeolite substance according to anyone of claims 1 to 3, wherein the following third-2 step is performedbetween the third step and the fourth step, and the substance obtainedin the third-2 step is used instead of as the precursor (B) in thefourth step: Third-2 Step: a step of acid-treating a part or entirety ofthe precursor (B) obtained in the third step.
 5. The process forproducing a zeolite substance according to any one of claims 1 to 4,wherein in the third step, a compound containing at least one elementselected from the elements belonging to Groups 3 to 14 of the periodictable is present together with the acid-treated precursor (A) obtainedin the second step.
 6. The process for producing a zeolite substanceaccording to any one of claims 1 to 5, wherein the template compound isa nitrogen-containing compound.
 7. The process for producing a zeolitesubstance according to claim 6, wherein the nitrogen-containing compoundis an amine and/or quaternary ammonium compound.
 8. The process forproducing a zeolite substance according to claim 6, wherein thenitrogen-containing compound is at least one member selected from thegroup consisting of piperidine, hexamethyleneimine and a mixture ofpiperidine and hexamethyleneimine.
 9. The process for producing azeolite substance according to any one of claims 2 to 8, wherein theboron-containing compound is at least one member selected from the groupconsisting of boric acid, borate, boron oxide, boron halide andtrialkylborons.
 10. The process for producing a zeolite substanceaccording to any one of claims 1 to 9, wherein the silicon-containingcompound is at least one member selected from the group consisting ofsilicic acid, silicate, silicon oxide, silicon halide, fumed silicas,tetraalkyl ortho-silicates and colloidal silica.
 11. The process forproducing a zeolite substance according to any one of claims 2 to 10,wherein the ratio between boron and silicon in the mixture of the firststep is boron:silicon=0.01 to 10:1 in terms of the molar ratio.
 12. Theprocess for producing a zeolite substance according to any one of claims2 to 11, wherein the ratio between boron and silicon in the mixture ofthe first step is boron:silicon=0.05 to 5:1 in terms of the molar ratio.13. The process for producing a zeolite substance according to any oneof claims 1 to 12, wherein the ratio between water and silicon in themixture of the first step is water:silicon=5 to 200:1 in terms of themolar ratio.
 14. The process for producing a zeolite substance accordingto any one of claims 1 to 13, wherein the ratio between the templatecompound and silicon in the mixture of the first step is templatecompound:silicon=0.1 to 5:1 in terms of the molar ratio.
 15. The processfor producing a zeolite substance according to any one of claims 1 to14, wherein the heating temperature in the first step is from 110 to200° C.
 16. The process for producing a zeolite substance according toany one of claims 1 to 15, wherein the acid used for the acid-treated inthe second step is a nitric acid.
 17. The process for producing azeolite substance according to any one of claims 1 to 16, wherein theheating temperature in the third step is from 110 to 200° C.
 18. Theprocess for producing a zeolite substance according to any one of claims1 to 17, wherein the calcining temperature in the fourth step is from200 to 700° C.
 19. The process for producing a zeolite substanceaccording to any one of claims 3 to 18, wherein the calciningtemperature in the first-2 step is from 200 to 700° C.
 20. The processfor producing a zeolite substance according to any one of claims 1 to19, wherein in the third step, the acid-treated precursor (A) obtainedin the second step and the mixture containing a template compound andwater are previously mixed and then heated.
 21. The process forproducing a zeolite substance according to any one of claims 1 to 20,wherein a dry gel method of charging the acid-treated precursor (A)obtained in the second step and the mixture containing a templatecompound and water while isolating the precursor (A) and the mixturefrom each other, and contacting the vapor of the mixture containing atemplate compound and water with a mixture of a compound containing atleast one element selected from Group 3 to Group 14 elements of theperiodic table, and the precursor (A), in the third step.
 22. Aprecursor obtained in the third step of the process according to any oneof claims 1-21.
 23. The precursor according to claim 22 which has alayered structure.
 24. The process for producing a zeolite substanceaccording to any one of 5 to 21, wherein the at least one elementselected from the elements belonging to Groups 3 to 14 of the periodictable is at least one element selected from the group consisting oftitanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum,tungsten, manganese, iron, cobalt, nickel, zinc, gallium, indium, tinand lead.
 25. A metallosilicate substance having an MWW structurecontaining at least one element selected from the elements belonging toGroups 3 to 14, in the Period 4 or more of the periodic table.
 26. Ametallosilicate substance having an MWW structure containing at leastone element selected from the elements belonging to Groups 3 to 14, inthe Period 5 or more of the periodic table.
 27. A metallosilicatesubstance having an MWW structure containing at least one elementselected from the group consisting of titanium, zirconium, vanadium,niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron,cobalt, nickel, zinc, gallium, indium, tin and lead.
 28. Ametallosilicate substance for a zeolite substance having an MWWstructure produced by the process according to any one of claims 1-21and
 24. 29. A layered precursor metallosilicate substance for a zeolitesubstance having an MWW structure containing at least one elementselected from the elements belonging to Groups 3 to 14, in the Period 4or more of the periodic table.
 30. A layered precursor metallosilicatesubstance for a zeolite substance having an MWW structure containing atleast one element selected from the elements belonging to Groups 3 to14, in the Period 5 or more of the periodic table.
 31. A layeredprecursor metallosilicate substance for a zeolite substance having anMWW structure containing at least one element selected from the groupconsisting of titanium, zirconium, vanadium, niobium, tantalum,chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, zinc,gallium, indium, tin and lead.
 32. A layered precursor metallosilicatesubstance for a zeolite substance having an MWW structure produced bythe process according to any one of claims 1-21 and
 24. 33. A zeolitesubstance produced by the process according to any one of claims 1-21and
 24. 34. A process for producing a layered precursor for a zeolitesubstance, comprising the following first to third steps: First Step: astep of heating a mixture containing a template compound, a compoundcontaining a Group 13 element of the periodic table, asilicon-containing compound and water to obtain a precursor (A); SecondStep: a step of acid-treating the precursor (A) obtained in the firststep; Third Step: a step of heating the acid-treated precursor (A)obtained in the second step together with a mixture containing atemplate compound and water to obtain a layered precursor.
 35. A layeredprecursor for a zeolite substance, produced by the process according toclaim 34.